The Mercury Grand PreQ15s is a fully discrete mono studio channel with 3-band equalizer, high & low pass filters and fully balanced transformer-coupled inputs and outputs. The GPQ15s has many additions to the classic circuit as well as all the modern features you will require packed into a solidly built 1U chassis. The Mercury GPQ15s boasts premium components, custom transformers, and is proudly built in the USA. The GPQ15s comes with an external premium quality power supply, the Mercury DC-1.

The Mercury Grand PreQ15s (GPQ15s) Studio Channel contains the Mercury Grand Pre Microphone Amplifier, Line Input Amplifier, Response Selection, High and Low-Frequency Filter Circuits and Output Level Control.

Facilities

Direct Mic/Line Switch:

When not engaged, the input XLR at the rear of the GPQ15s is the input source for either mic or line inputs. When the switch is engaged, the 1/4" jack (below the switch) becomes the input source, accepting an instrument-level signal (bass or guitar). This jack uses our Mercury FDI (Fet Direct Input) MKII circuit to convert to mic level and runs into the input transformer and complete GPQ15s circuits for the ability to have amazing control and tone on ‘direct’ recordings.

Direct Input (1/4" Jack):

This input is used when the Direct Mic/Line Switch is engaged for instrument level sources, giving you the ability to record guitar or bass directly.

Gain Control (Course Gain - Input Attenuator):

0dB and -12dB for line level sources, -24dB, -36dB, -48dB and -60dB for mic level sources.

Fine Gain Control:

At the 12 o’clock position, the Fine Gain Control is at 0dB, and the amount of input gain is the same as shown on the Gain Control or Course Gain (to the left). Turning the Fine Gain Control counter-clockwise, you can reduce the amount of gain up to -8dB. Turning the Fine Gain Control clockwise, you can add up to +8dB of gain, in addition to the amount shown on the Gain Control or Course Gain.

Output Level Control (Fader):

The Output Level Control allows you to reduce the level of the output of the GPQ15s. This works like the fader on your console's input channel. Turn the Output Level Control completely clockwise and the fader is ‘open’, allowing the maximum amount of output level. Turn the Output Level Control counter-clockwise to reduce the amount of output of the GPQ15s, all the way down to zero output level.

Phantom ON/Off LED (Red) and Phantom On/Off Switch:

When engaged, Phantom Power (48V DC) is on and will power your phantom powered microphone.

Phase ON/Off LED (White) and Phase On/Off Switch:

When not engaged, the phase is ‘normal’ or Pin 2 hot. When engaged, the phase is ‘reversed’ or Pin 3 hot.

EQ In/Out LED (Blue) and EQ In/Out Switch:

When not engaged, the EQ Section (Treble, Presence and Bass) are ‘out’. When engaged, the EQ Section is ‘In’.

Treble Controls

Treble Frequency Selection: 5k, 7k, 10k or 16k [Left]

Treble Cut/ Boost: This is a continuously variable control giving you a cut or boost of 11dB at 5k, 7k, 10k or 16k.

Presence Controls

Presence Frequency Selection: 350Hz, 700Hz, 1.2k, 2.4k, 3.6k, 4.7k and 6.8k [Left]

Presence Cut/ Boost: This is a continuously variable control giving you a cut or boost of 14dB at 350Hz, 700Hz, 1.2k, 2.4k, 3.6k, 4.7k and 6.8k.

Originally the circuit had an ‘Off’ position, instead we added 350Hz to facilitate more control when recording drums, etc.

Bass Controls

Bass Frequency Selection:35Hz, 50Hz, 100Hz and 160Hz [Left]

Bass Cut/ Boost: This is a continuously variable control giving you a cut or boost of 13dB at 35Hz, 50Hz, 100Hz and 160Hz.

Filter Section

Low Pass Frequency Section: 5k, 7k, 10k, 20k and Flat (Flat = filter is not engaged). This reduces the amplitude of the signal with frequencies higher than the ‘cutoff’ frequency selected on the Low Pass Frequency Selection switch.

High Pass Frequency Section: 220Hz, 100Hz, 45Hz, 20Hz and Flat (Flat = filter is not engaged). This reduces the amplitude of the signal with frequencies lower than the ‘cutoff’ frequency selected on the High Pass Frequency Selection switch.

Originally the circuit had no 20Hz or 20k positions. We extended the range by adding these positions and making the filter section a more useful and modern tool.

Power

Power Indicator LED: When illuminated, this indicates the GPQ15s has power (DC) from the Mercury DC-1 PSU (Power Supply Unit).

Mercury DC-1 PSU (Power Supply Unit)

The Mercury DC-1 is a real power supply. Designed by Mercury, to power professional audio equipment . The Mercury DC-1 uses a large Toroidal transformer and has dual regulation for clean, quiet power. Comes with a 5 pin XLR cable to run from Mercury DC-1 to the Mercury GPQ15s.